Preventing Inductive Noise As described previously, a noise filter can be used to prevent inductive noise from being generated on the out- put side. Alternatively, cables can be routed through a grounded metal pipe to prevent inductive noise. Keep- ing the metal pipe at least 30 cm away from the signal line considerably reduces inductive noise. Power supply Metal pipe IM Signal line 30 cm min. Controller Fig 2.11 Countermeasures Against Inductive Noise Counteracting RMS Radio noise is generated from the MxC as well as from the input and output lines. To reduce radio noise, install noise filters on both input and output sides, and also install the MxC in a totally enclosed steel box.
The cable between the MxC and the motor should be as short as possible. Steel box MCCB Power supply IM Fig 2.12 Countermeasures Against Radio Interference Cable Length between the MxC and Motor If the cable between the MxC and the motor is compartively long, the high-frequency leakage current will increase, causing the MxC output current to increase as well. This may affect peripheral devices. To prevent this, adjust the carrier frequency (set in C6-01, C6-02) as shown in Table 2.5 (for details, refer to Chapter 5 Parameters and Settings ).
Table 2.5 Cable Length between MxC and Motor 2- 13 MxC N oise No filt ise er fil ter MxC Cable length 50 m max 100 m max More than 100 m Carrier frequency 12 kHz max 8 kHz max 4 kHz max